xref: /freebsd/sys/contrib/openzfs/module/unicode/u8_textprep.c (revision b197d4b893974c9eb4d7b38704c6d5c486235d6f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 
27 
28 
29 /*
30  * UTF-8 text preparation functions (PSARC/2007/149, PSARC/2007/458).
31  *
32  * Man pages: u8_textprep_open(9F), u8_textprep_buf(9F), u8_textprep_close(9F),
33  * u8_textprep_str(9F), u8_strcmp(9F), and u8_validate(9F). See also
34  * the section 3C man pages.
35  * Interface stability: Committed.
36  */
37 
38 #include <sys/types.h>
39 #include <sys/string.h>
40 #include <sys/param.h>
41 #include <sys/sysmacros.h>
42 #include <sys/debug.h>
43 #include <sys/kmem.h>
44 #include <sys/sunddi.h>
45 #include <sys/u8_textprep.h>
46 #include <sys/byteorder.h>
47 #include <sys/errno.h>
48 #include <sys/u8_textprep_data.h>
49 #include <sys/mod.h>
50 
51 /* The maximum possible number of bytes in a UTF-8 character. */
52 #define	U8_MB_CUR_MAX			(4)
53 
54 /*
55  * The maximum number of bytes needed for a UTF-8 character to cover
56  * U+0000 - U+FFFF, i.e., the coding space of now deprecated UCS-2.
57  */
58 #define	U8_MAX_BYTES_UCS2		(3)
59 
60 /* The maximum possible number of bytes in a Stream-Safe Text. */
61 #define	U8_STREAM_SAFE_TEXT_MAX		(128)
62 
63 /*
64  * The maximum number of characters in a combining/conjoining sequence and
65  * the actual upperbound limit of a combining/conjoining sequence.
66  */
67 #define	U8_MAX_CHARS_A_SEQ		(32)
68 #define	U8_UPPER_LIMIT_IN_A_SEQ		(31)
69 
70 /* The combining class value for Starter. */
71 #define	U8_COMBINING_CLASS_STARTER	(0)
72 
73 /*
74  * Some Hangul related macros at below.
75  *
76  * The first and the last of Hangul syllables, Hangul Jamo Leading consonants,
77  * Vowels, and optional Trailing consonants in Unicode scalar values.
78  *
79  * Please be noted that the U8_HANGUL_JAMO_T_FIRST is 0x11A7 at below not
80  * the actual U+11A8. This is due to that the trailing consonant is optional
81  * and thus we are doing a pre-calculation of subtracting one.
82  *
83  * Each of 19 modern leading consonants has total 588 possible syllables since
84  * Hangul has 21 modern vowels and 27 modern trailing consonants plus 1 for
85  * no trailing consonant case, i.e., 21 x 28 = 588.
86  *
87  * We also have bunch of Hangul related macros at below. Please bear in mind
88  * that the U8_HANGUL_JAMO_1ST_BYTE can be used to check whether it is
89  * a Hangul Jamo or not but the value does not guarantee that it is a Hangul
90  * Jamo; it just guarantee that it will be most likely.
91  */
92 #define	U8_HANGUL_SYL_FIRST		(0xAC00U)
93 #define	U8_HANGUL_SYL_LAST		(0xD7A3U)
94 
95 #define	U8_HANGUL_JAMO_L_FIRST		(0x1100U)
96 #define	U8_HANGUL_JAMO_L_LAST		(0x1112U)
97 #define	U8_HANGUL_JAMO_V_FIRST		(0x1161U)
98 #define	U8_HANGUL_JAMO_V_LAST		(0x1175U)
99 #define	U8_HANGUL_JAMO_T_FIRST		(0x11A7U)
100 #define	U8_HANGUL_JAMO_T_LAST		(0x11C2U)
101 
102 #define	U8_HANGUL_V_COUNT		(21)
103 #define	U8_HANGUL_VT_COUNT		(588)
104 #define	U8_HANGUL_T_COUNT		(28)
105 
106 #define	U8_HANGUL_JAMO_1ST_BYTE		(0xE1U)
107 
108 #define	U8_SAVE_HANGUL_AS_UTF8(s, i, j, k, b) \
109 	(s)[(i)] = (uchar_t)(0xE0U | ((uint32_t)(b) & 0xF000U) >> 12); \
110 	(s)[(j)] = (uchar_t)(0x80U | ((uint32_t)(b) & 0x0FC0U) >> 6); \
111 	(s)[(k)] = (uchar_t)(0x80U | ((uint32_t)(b) & 0x003FU));
112 
113 #define	U8_HANGUL_JAMO_L(u) \
114 	((u) >= U8_HANGUL_JAMO_L_FIRST && (u) <= U8_HANGUL_JAMO_L_LAST)
115 
116 #define	U8_HANGUL_JAMO_V(u) \
117 	((u) >= U8_HANGUL_JAMO_V_FIRST && (u) <= U8_HANGUL_JAMO_V_LAST)
118 
119 #define	U8_HANGUL_JAMO_T(u) \
120 	((u) > U8_HANGUL_JAMO_T_FIRST && (u) <= U8_HANGUL_JAMO_T_LAST)
121 
122 #define	U8_HANGUL_JAMO(u) \
123 	((u) >= U8_HANGUL_JAMO_L_FIRST && (u) <= U8_HANGUL_JAMO_T_LAST)
124 
125 #define	U8_HANGUL_SYLLABLE(u) \
126 	((u) >= U8_HANGUL_SYL_FIRST && (u) <= U8_HANGUL_SYL_LAST)
127 
128 #define	U8_HANGUL_COMPOSABLE_L_V(s, u) \
129 	((s) == U8_STATE_HANGUL_L && U8_HANGUL_JAMO_V((u)))
130 
131 #define	U8_HANGUL_COMPOSABLE_LV_T(s, u) \
132 	((s) == U8_STATE_HANGUL_LV && U8_HANGUL_JAMO_T((u)))
133 
134 /* The types of decomposition mappings. */
135 #define	U8_DECOMP_BOTH			(0xF5U)
136 #define	U8_DECOMP_CANONICAL		(0xF6U)
137 
138 /* The indicator for 16-bit table. */
139 #define	U8_16BIT_TABLE_INDICATOR	(0x8000U)
140 
141 /* The following are some convenience macros. */
142 #define	U8_PUT_3BYTES_INTO_UTF32(u, b1, b2, b3)  \
143 	(u) = ((((uint32_t)(b1) & 0x0F) << 12) | \
144 		(((uint32_t)(b2) & 0x3F) << 6)  | \
145 		((uint32_t)(b3) & 0x3F));
146 
147 #define	U8_SIMPLE_SWAP(a, b, t) \
148 	(t) = (a); \
149 	(a) = (b); \
150 	(b) = (t);
151 
152 #define	U8_ASCII_TOUPPER(c) \
153 	(((c) >= 'a' && (c) <= 'z') ? (c) - 'a' + 'A' : (c))
154 
155 #define	U8_ASCII_TOLOWER(c) \
156 	(((c) >= 'A' && (c) <= 'Z') ? (c) - 'A' + 'a' : (c))
157 
158 #define	U8_ISASCII(c)			(((uchar_t)(c)) < 0x80U)
159 /*
160  * The following macro assumes that the two characters that are to be
161  * swapped are adjacent to each other and 'a' comes before 'b'.
162  *
163  * If the assumptions are not met, then, the macro will fail.
164  */
165 #define	U8_SWAP_COMB_MARKS(a, b) \
166 	for (k = 0; k < disp[(a)]; k++) \
167 		u8t[k] = u8s[start[(a)] + k]; \
168 	for (k = 0; k < disp[(b)]; k++) \
169 		u8s[start[(a)] + k] = u8s[start[(b)] + k]; \
170 	start[(b)] = start[(a)] + disp[(b)]; \
171 	for (k = 0; k < disp[(a)]; k++) \
172 		u8s[start[(b)] + k] = u8t[k]; \
173 	U8_SIMPLE_SWAP(comb_class[(a)], comb_class[(b)], tc); \
174 	U8_SIMPLE_SWAP(disp[(a)], disp[(b)], tc);
175 
176 /* The possible states during normalization. */
177 typedef enum {
178 	U8_STATE_START = 0,
179 	U8_STATE_HANGUL_L = 1,
180 	U8_STATE_HANGUL_LV = 2,
181 	U8_STATE_HANGUL_LVT = 3,
182 	U8_STATE_HANGUL_V = 4,
183 	U8_STATE_HANGUL_T = 5,
184 	U8_STATE_COMBINING_MARK = 6
185 } u8_normalization_states_t;
186 
187 /*
188  * The three vectors at below are used to check bytes of a given UTF-8
189  * character are valid and not containing any malformed byte values.
190  *
191  * We used to have a quite relaxed UTF-8 binary representation but then there
192  * was some security related issues and so the Unicode Consortium defined
193  * and announced the UTF-8 Corrigendum at Unicode 3.1 and then refined it
194  * one more time at the Unicode 3.2. The following three tables are based on
195  * that.
196  */
197 
198 #define	U8_ILLEGAL_NEXT_BYTE_COMMON(c)	((c) < 0x80 || (c) > 0xBF)
199 
200 #define	I_				U8_ILLEGAL_CHAR
201 #define	O_				U8_OUT_OF_RANGE_CHAR
202 
203 static const int8_t u8_number_of_bytes[0x100] = {
204 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
205 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
206 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
207 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
208 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
209 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
210 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
211 	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
212 
213 /*	80  81  82  83  84  85  86  87  88  89  8A  8B  8C  8D  8E  8F  */
214 	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
215 
216 /*  	90  91  92  93  94  95  96  97  98  99  9A  9B  9C  9D  9E  9F  */
217 	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
218 
219 /*  	A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC  AD  AE  AF  */
220 	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
221 
222 /*	B0  B1  B2  B3  B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE  BF  */
223 	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
224 
225 /*	C0  C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE  CF  */
226 	I_, I_, 2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,
227 
228 /*	D0  D1  D2  D3  D4  D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  */
229 	2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,
230 
231 /*	E0  E1  E2  E3  E4  E5  E6  E7  E8  E9  EA  EB  EC  ED  EE  EF  */
232 	3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,
233 
234 /*	F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC  FD  FE  FF  */
235 	4,  4,  4,  4,  4,  O_, O_, O_, O_, O_, O_, O_, O_, O_, O_, O_,
236 };
237 
238 #undef	I_
239 #undef	O_
240 
241 static const uint8_t u8_valid_min_2nd_byte[0x100] = {
242 	0,    0,    0,    0,    0,    0,    0,    0,
243 	0,    0,    0,    0,    0,    0,    0,    0,
244 	0,    0,    0,    0,    0,    0,    0,    0,
245 	0,    0,    0,    0,    0,    0,    0,    0,
246 	0,    0,    0,    0,    0,    0,    0,    0,
247 	0,    0,    0,    0,    0,    0,    0,    0,
248 	0,    0,    0,    0,    0,    0,    0,    0,
249 	0,    0,    0,    0,    0,    0,    0,    0,
250 	0,    0,    0,    0,    0,    0,    0,    0,
251 	0,    0,    0,    0,    0,    0,    0,    0,
252 	0,    0,    0,    0,    0,    0,    0,    0,
253 	0,    0,    0,    0,    0,    0,    0,    0,
254 	0,    0,    0,    0,    0,    0,    0,    0,
255 	0,    0,    0,    0,    0,    0,    0,    0,
256 	0,    0,    0,    0,    0,    0,    0,    0,
257 	0,    0,    0,    0,    0,    0,    0,    0,
258 	0,    0,    0,    0,    0,    0,    0,    0,
259 	0,    0,    0,    0,    0,    0,    0,    0,
260 	0,    0,    0,    0,    0,    0,    0,    0,
261 	0,    0,    0,    0,    0,    0,    0,    0,
262 	0,    0,    0,    0,    0,    0,    0,    0,
263 	0,    0,    0,    0,    0,    0,    0,    0,
264 	0,    0,    0,    0,    0,    0,    0,    0,
265 	0,    0,    0,    0,    0,    0,    0,    0,
266 /*	C0    C1    C2    C3    C4    C5    C6    C7    */
267 	0,    0,    0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
268 /*	C8    C9    CA    CB    CC    CD    CE    CF    */
269 	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
270 /*	D0    D1    D2    D3    D4    D5    D6    D7    */
271 	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
272 /*	D8    D9    DA    DB    DC    DD    DE    DF    */
273 	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
274 /*	E0    E1    E2    E3    E4    E5    E6    E7    */
275 	0xa0, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
276 /*	E8    E9    EA    EB    EC    ED    EE    EF    */
277 	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
278 /*	F0    F1    F2    F3    F4    F5    F6    F7    */
279 	0x90, 0x80, 0x80, 0x80, 0x80, 0,    0,    0,
280 	0,    0,    0,    0,    0,    0,    0,    0,
281 };
282 
283 static const uint8_t u8_valid_max_2nd_byte[0x100] = {
284 	0,    0,    0,    0,    0,    0,    0,    0,
285 	0,    0,    0,    0,    0,    0,    0,    0,
286 	0,    0,    0,    0,    0,    0,    0,    0,
287 	0,    0,    0,    0,    0,    0,    0,    0,
288 	0,    0,    0,    0,    0,    0,    0,    0,
289 	0,    0,    0,    0,    0,    0,    0,    0,
290 	0,    0,    0,    0,    0,    0,    0,    0,
291 	0,    0,    0,    0,    0,    0,    0,    0,
292 	0,    0,    0,    0,    0,    0,    0,    0,
293 	0,    0,    0,    0,    0,    0,    0,    0,
294 	0,    0,    0,    0,    0,    0,    0,    0,
295 	0,    0,    0,    0,    0,    0,    0,    0,
296 	0,    0,    0,    0,    0,    0,    0,    0,
297 	0,    0,    0,    0,    0,    0,    0,    0,
298 	0,    0,    0,    0,    0,    0,    0,    0,
299 	0,    0,    0,    0,    0,    0,    0,    0,
300 	0,    0,    0,    0,    0,    0,    0,    0,
301 	0,    0,    0,    0,    0,    0,    0,    0,
302 	0,    0,    0,    0,    0,    0,    0,    0,
303 	0,    0,    0,    0,    0,    0,    0,    0,
304 	0,    0,    0,    0,    0,    0,    0,    0,
305 	0,    0,    0,    0,    0,    0,    0,    0,
306 	0,    0,    0,    0,    0,    0,    0,    0,
307 	0,    0,    0,    0,    0,    0,    0,    0,
308 /*	C0    C1    C2    C3    C4    C5    C6    C7    */
309 	0,    0,    0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
310 /*	C8    C9    CA    CB    CC    CD    CE    CF    */
311 	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
312 /*	D0    D1    D2    D3    D4    D5    D6    D7    */
313 	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
314 /*	D8    D9    DA    DB    DC    DD    DE    DF    */
315 	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
316 /*	E0    E1    E2    E3    E4    E5    E6    E7    */
317 	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
318 /*	E8    E9    EA    EB    EC    ED    EE    EF    */
319 	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0x9f, 0xbf, 0xbf,
320 /*	F0    F1    F2    F3    F4    F5    F6    F7    */
321 	0xbf, 0xbf, 0xbf, 0xbf, 0x8f, 0,    0,    0,
322 	0,    0,    0,    0,    0,    0,    0,    0,
323 };
324 
325 
326 /*
327  * The u8_validate() validates on the given UTF-8 character string and
328  * calculate the byte length. It is quite similar to mblen(3C) except that
329  * this will validate against the list of characters if required and
330  * specific to UTF-8 and Unicode.
331  */
332 int
333 u8_validate(const char *u8str, size_t n, char **list, int flag, int *errnum)
334 {
335 	uchar_t *ib;
336 	uchar_t *ibtail;
337 	uchar_t **p;
338 	uchar_t *s1;
339 	uchar_t *s2;
340 	uchar_t f;
341 	int sz;
342 	size_t i;
343 	int ret_val;
344 	boolean_t second;
345 	boolean_t no_need_to_validate_entire;
346 	boolean_t check_additional;
347 	boolean_t validate_ucs2_range_only;
348 
349 	if (! u8str)
350 		return (0);
351 
352 	ib = (uchar_t *)u8str;
353 	ibtail = ib + n;
354 
355 	ret_val = 0;
356 
357 	no_need_to_validate_entire = ! (flag & U8_VALIDATE_ENTIRE);
358 	check_additional = flag & U8_VALIDATE_CHECK_ADDITIONAL;
359 	validate_ucs2_range_only = flag & U8_VALIDATE_UCS2_RANGE;
360 
361 	while (ib < ibtail) {
362 		/*
363 		 * The first byte of a UTF-8 character tells how many
364 		 * bytes will follow for the character. If the first byte
365 		 * is an illegal byte value or out of range value, we just
366 		 * return -1 with an appropriate error number.
367 		 */
368 		sz = u8_number_of_bytes[*ib];
369 		if (sz == U8_ILLEGAL_CHAR) {
370 			*errnum = EILSEQ;
371 			return (-1);
372 		}
373 
374 		if (sz == U8_OUT_OF_RANGE_CHAR ||
375 		    (validate_ucs2_range_only && sz > U8_MAX_BYTES_UCS2)) {
376 			*errnum = ERANGE;
377 			return (-1);
378 		}
379 
380 		/*
381 		 * If we don't have enough bytes to check on, that's also
382 		 * an error. As you can see, we give illegal byte sequence
383 		 * checking higher priority then EINVAL cases.
384 		 */
385 		if ((ibtail - ib) < sz) {
386 			*errnum = EINVAL;
387 			return (-1);
388 		}
389 
390 		if (sz == 1) {
391 			ib++;
392 			ret_val++;
393 		} else {
394 			/*
395 			 * Check on the multi-byte UTF-8 character. For more
396 			 * details on this, see comment added for the used
397 			 * data structures at the beginning of the file.
398 			 */
399 			f = *ib++;
400 			ret_val++;
401 			second = B_TRUE;
402 			for (i = 1; i < sz; i++) {
403 				if (second) {
404 					if (*ib < u8_valid_min_2nd_byte[f] ||
405 					    *ib > u8_valid_max_2nd_byte[f]) {
406 						*errnum = EILSEQ;
407 						return (-1);
408 					}
409 					second = B_FALSE;
410 				} else if (U8_ILLEGAL_NEXT_BYTE_COMMON(*ib)) {
411 					*errnum = EILSEQ;
412 					return (-1);
413 				}
414 				ib++;
415 				ret_val++;
416 			}
417 		}
418 
419 		if (check_additional) {
420 			for (p = (uchar_t **)list, i = 0; p[i]; i++) {
421 				s1 = ib - sz;
422 				s2 = p[i];
423 				while (s1 < ib) {
424 					if (*s1 != *s2 || *s2 == '\0')
425 						break;
426 					s1++;
427 					s2++;
428 				}
429 
430 				if (s1 >= ib && *s2 == '\0') {
431 					*errnum = EBADF;
432 					return (-1);
433 				}
434 			}
435 		}
436 
437 		if (no_need_to_validate_entire)
438 			break;
439 	}
440 
441 	return (ret_val);
442 }
443 
444 /*
445  * The do_case_conv() looks at the mapping tables and returns found
446  * bytes if any. If not found, the input bytes are returned. The function
447  * always terminate the return bytes with a null character assuming that
448  * there are plenty of room to do so.
449  *
450  * The case conversions are simple case conversions mapping a character to
451  * another character as specified in the Unicode data. The byte size of
452  * the mapped character could be different from that of the input character.
453  *
454  * The return value is the byte length of the returned character excluding
455  * the terminating null byte.
456  */
457 static size_t
458 do_case_conv(int uv, uchar_t *u8s, uchar_t *s, int sz, boolean_t is_it_toupper)
459 {
460 	size_t i;
461 	uint16_t b1 = 0;
462 	uint16_t b2 = 0;
463 	uint16_t b3 = 0;
464 	uint16_t b3_tbl;
465 	uint16_t b3_base;
466 	uint16_t b4 = 0;
467 	size_t start_id;
468 	size_t end_id;
469 
470 	/*
471 	 * At this point, the only possible values for sz are 2, 3, and 4.
472 	 * The u8s should point to a vector that is well beyond the size of
473 	 * 5 bytes.
474 	 */
475 	if (sz == 2) {
476 		b3 = u8s[0] = s[0];
477 		b4 = u8s[1] = s[1];
478 	} else if (sz == 3) {
479 		b2 = u8s[0] = s[0];
480 		b3 = u8s[1] = s[1];
481 		b4 = u8s[2] = s[2];
482 	} else if (sz == 4) {
483 		b1 = u8s[0] = s[0];
484 		b2 = u8s[1] = s[1];
485 		b3 = u8s[2] = s[2];
486 		b4 = u8s[3] = s[3];
487 	} else {
488 		/* This is not possible but just in case as a fallback. */
489 		if (is_it_toupper)
490 			*u8s = U8_ASCII_TOUPPER(*s);
491 		else
492 			*u8s = U8_ASCII_TOLOWER(*s);
493 		u8s[1] = '\0';
494 
495 		return (1);
496 	}
497 	u8s[sz] = '\0';
498 
499 	/*
500 	 * Let's find out if we have a corresponding character.
501 	 */
502 	b1 = u8_common_b1_tbl[uv][b1];
503 	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
504 		return ((size_t)sz);
505 
506 	b2 = u8_case_common_b2_tbl[uv][b1][b2];
507 	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
508 		return ((size_t)sz);
509 
510 	if (is_it_toupper) {
511 		b3_tbl = u8_toupper_b3_tbl[uv][b2][b3].tbl_id;
512 		if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
513 			return ((size_t)sz);
514 
515 		start_id = u8_toupper_b4_tbl[uv][b3_tbl][b4];
516 		end_id = u8_toupper_b4_tbl[uv][b3_tbl][b4 + 1];
517 
518 		/* Either there is no match or an error at the table. */
519 		if (start_id >= end_id || (end_id - start_id) > U8_MB_CUR_MAX)
520 			return ((size_t)sz);
521 
522 		b3_base = u8_toupper_b3_tbl[uv][b2][b3].base;
523 
524 		for (i = 0; start_id < end_id; start_id++)
525 			u8s[i++] = u8_toupper_final_tbl[uv][b3_base + start_id];
526 	} else {
527 		b3_tbl = u8_tolower_b3_tbl[uv][b2][b3].tbl_id;
528 		if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
529 			return ((size_t)sz);
530 
531 		start_id = u8_tolower_b4_tbl[uv][b3_tbl][b4];
532 		end_id = u8_tolower_b4_tbl[uv][b3_tbl][b4 + 1];
533 
534 		if (start_id >= end_id || (end_id - start_id) > U8_MB_CUR_MAX)
535 			return ((size_t)sz);
536 
537 		b3_base = u8_tolower_b3_tbl[uv][b2][b3].base;
538 
539 		for (i = 0; start_id < end_id; start_id++)
540 			u8s[i++] = u8_tolower_final_tbl[uv][b3_base + start_id];
541 	}
542 
543 	/*
544 	 * If i is still zero, that means there is no corresponding character.
545 	 */
546 	if (i == 0)
547 		return ((size_t)sz);
548 
549 	u8s[i] = '\0';
550 
551 	return (i);
552 }
553 
554 /*
555  * The do_case_compare() function compares the two input strings, s1 and s2,
556  * one character at a time doing case conversions if applicable and return
557  * the comparison result as like strcmp().
558  *
559  * Since, in empirical sense, most of text data are 7-bit ASCII characters,
560  * we treat the 7-bit ASCII characters as a special case trying to yield
561  * faster processing time.
562  */
563 static int
564 do_case_compare(size_t uv, uchar_t *s1, uchar_t *s2, size_t n1,
565     size_t n2, boolean_t is_it_toupper, int *errnum)
566 {
567 	int f;
568 	int sz1;
569 	int sz2;
570 	size_t j;
571 	size_t i1;
572 	size_t i2;
573 	uchar_t u8s1[U8_MB_CUR_MAX + 1];
574 	uchar_t u8s2[U8_MB_CUR_MAX + 1];
575 
576 	i1 = i2 = 0;
577 	while (i1 < n1 && i2 < n2) {
578 		/*
579 		 * Find out what would be the byte length for this UTF-8
580 		 * character at string s1 and also find out if this is
581 		 * an illegal start byte or not and if so, issue a proper
582 		 * error number and yet treat this byte as a character.
583 		 */
584 		sz1 = u8_number_of_bytes[*s1];
585 		if (sz1 < 0) {
586 			*errnum = EILSEQ;
587 			sz1 = 1;
588 		}
589 
590 		/*
591 		 * For 7-bit ASCII characters mainly, we do a quick case
592 		 * conversion right at here.
593 		 *
594 		 * If we don't have enough bytes for this character, issue
595 		 * an EINVAL error and use what are available.
596 		 *
597 		 * If we have enough bytes, find out if there is
598 		 * a corresponding uppercase character and if so, copy over
599 		 * the bytes for a comparison later. If there is no
600 		 * corresponding uppercase character, then, use what we have
601 		 * for the comparison.
602 		 */
603 		if (sz1 == 1) {
604 			if (is_it_toupper)
605 				u8s1[0] = U8_ASCII_TOUPPER(*s1);
606 			else
607 				u8s1[0] = U8_ASCII_TOLOWER(*s1);
608 			s1++;
609 			u8s1[1] = '\0';
610 		} else if ((i1 + sz1) > n1) {
611 			*errnum = EINVAL;
612 			for (j = 0; (i1 + j) < n1; )
613 				u8s1[j++] = *s1++;
614 			u8s1[j] = '\0';
615 		} else {
616 			(void) do_case_conv(uv, u8s1, s1, sz1, is_it_toupper);
617 			s1 += sz1;
618 		}
619 
620 		/* Do the same for the string s2. */
621 		sz2 = u8_number_of_bytes[*s2];
622 		if (sz2 < 0) {
623 			*errnum = EILSEQ;
624 			sz2 = 1;
625 		}
626 
627 		if (sz2 == 1) {
628 			if (is_it_toupper)
629 				u8s2[0] = U8_ASCII_TOUPPER(*s2);
630 			else
631 				u8s2[0] = U8_ASCII_TOLOWER(*s2);
632 			s2++;
633 			u8s2[1] = '\0';
634 		} else if ((i2 + sz2) > n2) {
635 			*errnum = EINVAL;
636 			for (j = 0; (i2 + j) < n2; )
637 				u8s2[j++] = *s2++;
638 			u8s2[j] = '\0';
639 		} else {
640 			(void) do_case_conv(uv, u8s2, s2, sz2, is_it_toupper);
641 			s2 += sz2;
642 		}
643 
644 		/* Now compare the two characters. */
645 		if (sz1 == 1 && sz2 == 1) {
646 			if (*u8s1 > *u8s2)
647 				return (1);
648 			if (*u8s1 < *u8s2)
649 				return (-1);
650 		} else {
651 			f = strcmp((const char *)u8s1, (const char *)u8s2);
652 			if (f != 0)
653 				return (f);
654 		}
655 
656 		/*
657 		 * They were the same. Let's move on to the next
658 		 * characters then.
659 		 */
660 		i1 += sz1;
661 		i2 += sz2;
662 	}
663 
664 	/*
665 	 * We compared until the end of either or both strings.
666 	 *
667 	 * If we reached to or went over the ends for the both, that means
668 	 * they are the same.
669 	 *
670 	 * If we reached only one of the two ends, that means the other string
671 	 * has something which then the fact can be used to determine
672 	 * the return value.
673 	 */
674 	if (i1 >= n1) {
675 		if (i2 >= n2)
676 			return (0);
677 		return (-1);
678 	}
679 	return (1);
680 }
681 
682 /*
683  * The combining_class() function checks on the given bytes and find out
684  * the corresponding Unicode combining class value. The return value 0 means
685  * it is a Starter. Any illegal UTF-8 character will also be treated as
686  * a Starter.
687  */
688 static uchar_t
689 combining_class(size_t uv, uchar_t *s, size_t sz)
690 {
691 	uint16_t b1 = 0;
692 	uint16_t b2 = 0;
693 	uint16_t b3 = 0;
694 	uint16_t b4 = 0;
695 
696 	if (sz == 1 || sz > 4)
697 		return (0);
698 
699 	if (sz == 2) {
700 		b3 = s[0];
701 		b4 = s[1];
702 	} else if (sz == 3) {
703 		b2 = s[0];
704 		b3 = s[1];
705 		b4 = s[2];
706 	} else if (sz == 4) {
707 		b1 = s[0];
708 		b2 = s[1];
709 		b3 = s[2];
710 		b4 = s[3];
711 	}
712 
713 	b1 = u8_common_b1_tbl[uv][b1];
714 	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
715 		return (0);
716 
717 	b2 = u8_combining_class_b2_tbl[uv][b1][b2];
718 	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
719 		return (0);
720 
721 	b3 = u8_combining_class_b3_tbl[uv][b2][b3];
722 	if (b3 == U8_TBL_ELEMENT_NOT_DEF)
723 		return (0);
724 
725 	return (u8_combining_class_b4_tbl[uv][b3][b4]);
726 }
727 
728 /*
729  * The do_decomp() function finds out a matching decomposition if any
730  * and return. If there is no match, the input bytes are copied and returned.
731  * The function also checks if there is a Hangul, decomposes it if necessary
732  * and returns.
733  *
734  * To save time, a single byte 7-bit ASCII character should be handled by
735  * the caller.
736  *
737  * The function returns the number of bytes returned sans always terminating
738  * the null byte. It will also return a state that will tell if there was
739  * a Hangul character decomposed which then will be used by the caller.
740  */
741 static size_t
742 do_decomp(size_t uv, uchar_t *u8s, uchar_t *s, int sz,
743     boolean_t canonical_decomposition, u8_normalization_states_t *state)
744 {
745 	uint16_t b1 = 0;
746 	uint16_t b2 = 0;
747 	uint16_t b3 = 0;
748 	uint16_t b3_tbl;
749 	uint16_t b3_base;
750 	uint16_t b4 = 0;
751 	size_t start_id;
752 	size_t end_id;
753 	size_t i;
754 	uint32_t u1;
755 
756 	if (sz == 2) {
757 		b3 = u8s[0] = s[0];
758 		b4 = u8s[1] = s[1];
759 		u8s[2] = '\0';
760 	} else if (sz == 3) {
761 		/* Convert it to a Unicode scalar value. */
762 		U8_PUT_3BYTES_INTO_UTF32(u1, s[0], s[1], s[2]);
763 
764 		/*
765 		 * If this is a Hangul syllable, we decompose it into
766 		 * a leading consonant, a vowel, and an optional trailing
767 		 * consonant and then return.
768 		 */
769 		if (U8_HANGUL_SYLLABLE(u1)) {
770 			u1 -= U8_HANGUL_SYL_FIRST;
771 
772 			b1 = U8_HANGUL_JAMO_L_FIRST + u1 / U8_HANGUL_VT_COUNT;
773 			b2 = U8_HANGUL_JAMO_V_FIRST + (u1 % U8_HANGUL_VT_COUNT)
774 			    / U8_HANGUL_T_COUNT;
775 			b3 = u1 % U8_HANGUL_T_COUNT;
776 
777 			U8_SAVE_HANGUL_AS_UTF8(u8s, 0, 1, 2, b1);
778 			U8_SAVE_HANGUL_AS_UTF8(u8s, 3, 4, 5, b2);
779 			if (b3) {
780 				b3 += U8_HANGUL_JAMO_T_FIRST;
781 				U8_SAVE_HANGUL_AS_UTF8(u8s, 6, 7, 8, b3);
782 
783 				u8s[9] = '\0';
784 				*state = U8_STATE_HANGUL_LVT;
785 				return (9);
786 			}
787 
788 			u8s[6] = '\0';
789 			*state = U8_STATE_HANGUL_LV;
790 			return (6);
791 		}
792 
793 		b2 = u8s[0] = s[0];
794 		b3 = u8s[1] = s[1];
795 		b4 = u8s[2] = s[2];
796 		u8s[3] = '\0';
797 
798 		/*
799 		 * If this is a Hangul Jamo, we know there is nothing
800 		 * further that we can decompose.
801 		 */
802 		if (U8_HANGUL_JAMO_L(u1)) {
803 			*state = U8_STATE_HANGUL_L;
804 			return (3);
805 		}
806 
807 		if (U8_HANGUL_JAMO_V(u1)) {
808 			if (*state == U8_STATE_HANGUL_L)
809 				*state = U8_STATE_HANGUL_LV;
810 			else
811 				*state = U8_STATE_HANGUL_V;
812 			return (3);
813 		}
814 
815 		if (U8_HANGUL_JAMO_T(u1)) {
816 			if (*state == U8_STATE_HANGUL_LV)
817 				*state = U8_STATE_HANGUL_LVT;
818 			else
819 				*state = U8_STATE_HANGUL_T;
820 			return (3);
821 		}
822 	} else if (sz == 4) {
823 		b1 = u8s[0] = s[0];
824 		b2 = u8s[1] = s[1];
825 		b3 = u8s[2] = s[2];
826 		b4 = u8s[3] = s[3];
827 		u8s[4] = '\0';
828 	} else {
829 		/*
830 		 * This is a fallback and should not happen if the function
831 		 * was called properly.
832 		 */
833 		u8s[0] = s[0];
834 		u8s[1] = '\0';
835 		*state = U8_STATE_START;
836 		return (1);
837 	}
838 
839 	/*
840 	 * At this point, this routine does not know what it would get.
841 	 * The caller should sort it out if the state isn't a Hangul one.
842 	 */
843 	*state = U8_STATE_START;
844 
845 	/* Try to find matching decomposition mapping byte sequence. */
846 	b1 = u8_common_b1_tbl[uv][b1];
847 	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
848 		return ((size_t)sz);
849 
850 	b2 = u8_decomp_b2_tbl[uv][b1][b2];
851 	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
852 		return ((size_t)sz);
853 
854 	b3_tbl = u8_decomp_b3_tbl[uv][b2][b3].tbl_id;
855 	if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
856 		return ((size_t)sz);
857 
858 	/*
859 	 * If b3_tbl is bigger than or equal to U8_16BIT_TABLE_INDICATOR
860 	 * which is 0x8000, this means we couldn't fit the mappings into
861 	 * the cardinality of a unsigned byte.
862 	 */
863 	if (b3_tbl >= U8_16BIT_TABLE_INDICATOR) {
864 		b3_tbl -= U8_16BIT_TABLE_INDICATOR;
865 		start_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4];
866 		end_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
867 	} else {
868 		// cppcheck-suppress arrayIndexOutOfBoundsCond
869 		start_id = u8_decomp_b4_tbl[uv][b3_tbl][b4];
870 		// cppcheck-suppress arrayIndexOutOfBoundsCond
871 		end_id = u8_decomp_b4_tbl[uv][b3_tbl][b4 + 1];
872 	}
873 
874 	/* This also means there wasn't any matching decomposition. */
875 	if (start_id >= end_id)
876 		return ((size_t)sz);
877 
878 	/*
879 	 * The final table for decomposition mappings has three types of
880 	 * byte sequences depending on whether a mapping is for compatibility
881 	 * decomposition, canonical decomposition, or both like the following:
882 	 *
883 	 * (1) Compatibility decomposition mappings:
884 	 *
885 	 *	+---+---+-...-+---+
886 	 *	| B0| B1| ... | Bm|
887 	 *	+---+---+-...-+---+
888 	 *
889 	 *	The first byte, B0, is always less than 0xF5 (U8_DECOMP_BOTH).
890 	 *
891 	 * (2) Canonical decomposition mappings:
892 	 *
893 	 *	+---+---+---+-...-+---+
894 	 *	| T | b0| b1| ... | bn|
895 	 *	+---+---+---+-...-+---+
896 	 *
897 	 *	where the first byte, T, is 0xF6 (U8_DECOMP_CANONICAL).
898 	 *
899 	 * (3) Both mappings:
900 	 *
901 	 *	+---+---+---+---+-...-+---+---+---+-...-+---+
902 	 *	| T | D | b0| b1| ... | bn| B0| B1| ... | Bm|
903 	 *	+---+---+---+---+-...-+---+---+---+-...-+---+
904 	 *
905 	 *	where T is 0xF5 (U8_DECOMP_BOTH) and D is a displacement
906 	 *	byte, b0 to bn are canonical mapping bytes and B0 to Bm are
907 	 *	compatibility mapping bytes.
908 	 *
909 	 * Note that compatibility decomposition means doing recursive
910 	 * decompositions using both compatibility decomposition mappings and
911 	 * canonical decomposition mappings. On the other hand, canonical
912 	 * decomposition means doing recursive decompositions using only
913 	 * canonical decomposition mappings. Since the table we have has gone
914 	 * through the recursions already, we do not need to do so during
915 	 * runtime, i.e., the table has been completely flattened out
916 	 * already.
917 	 */
918 
919 	b3_base = u8_decomp_b3_tbl[uv][b2][b3].base;
920 
921 	/* Get the type, T, of the byte sequence. */
922 	b1 = u8_decomp_final_tbl[uv][b3_base + start_id];
923 
924 	/*
925 	 * If necessary, adjust start_id, end_id, or both. Note that if
926 	 * this is compatibility decomposition mapping, there is no
927 	 * adjustment.
928 	 */
929 	if (canonical_decomposition) {
930 		/* Is the mapping only for compatibility decomposition? */
931 		if (b1 < U8_DECOMP_BOTH)
932 			return ((size_t)sz);
933 
934 		start_id++;
935 
936 		if (b1 == U8_DECOMP_BOTH) {
937 			end_id = start_id +
938 			    u8_decomp_final_tbl[uv][b3_base + start_id];
939 			start_id++;
940 		}
941 	} else {
942 		/*
943 		 * Unless this is a compatibility decomposition mapping,
944 		 * we adjust the start_id.
945 		 */
946 		if (b1 == U8_DECOMP_BOTH) {
947 			start_id++;
948 			start_id += u8_decomp_final_tbl[uv][b3_base + start_id];
949 		} else if (b1 == U8_DECOMP_CANONICAL) {
950 			start_id++;
951 		}
952 	}
953 
954 	for (i = 0; start_id < end_id; start_id++)
955 		u8s[i++] = u8_decomp_final_tbl[uv][b3_base + start_id];
956 	u8s[i] = '\0';
957 
958 	return (i);
959 }
960 
961 /*
962  * The find_composition_start() function uses the character bytes given and
963  * find out the matching composition mappings if any and return the address
964  * to the composition mappings as explained in the do_composition().
965  */
966 static uchar_t *
967 find_composition_start(size_t uv, uchar_t *s, size_t sz)
968 {
969 	uint16_t b1 = 0;
970 	uint16_t b2 = 0;
971 	uint16_t b3 = 0;
972 	uint16_t b3_tbl;
973 	uint16_t b3_base;
974 	uint16_t b4 = 0;
975 	size_t start_id;
976 	size_t end_id;
977 
978 	if (sz == 1) {
979 		b4 = s[0];
980 	} else if (sz == 2) {
981 		b3 = s[0];
982 		b4 = s[1];
983 	} else if (sz == 3) {
984 		b2 = s[0];
985 		b3 = s[1];
986 		b4 = s[2];
987 	} else if (sz == 4) {
988 		b1 = s[0];
989 		b2 = s[1];
990 		b3 = s[2];
991 		b4 = s[3];
992 	} else {
993 		/*
994 		 * This is a fallback and should not happen if the function
995 		 * was called properly.
996 		 */
997 		return (NULL);
998 	}
999 
1000 	b1 = u8_composition_b1_tbl[uv][b1];
1001 	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
1002 		return (NULL);
1003 
1004 	b2 = u8_composition_b2_tbl[uv][b1][b2];
1005 	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
1006 		return (NULL);
1007 
1008 	b3_tbl = u8_composition_b3_tbl[uv][b2][b3].tbl_id;
1009 	if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
1010 		return (NULL);
1011 
1012 	if (b3_tbl >= U8_16BIT_TABLE_INDICATOR) {
1013 		b3_tbl -= U8_16BIT_TABLE_INDICATOR;
1014 		start_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4];
1015 		end_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
1016 	} else {
1017 		// cppcheck-suppress arrayIndexOutOfBoundsCond
1018 		start_id = u8_composition_b4_tbl[uv][b3_tbl][b4];
1019 		// cppcheck-suppress arrayIndexOutOfBoundsCond
1020 		end_id = u8_composition_b4_tbl[uv][b3_tbl][b4 + 1];
1021 	}
1022 
1023 	if (start_id >= end_id)
1024 		return (NULL);
1025 
1026 	b3_base = u8_composition_b3_tbl[uv][b2][b3].base;
1027 
1028 	return ((uchar_t *)&(u8_composition_final_tbl[uv][b3_base + start_id]));
1029 }
1030 
1031 /*
1032  * The blocked() function checks on the combining class values of previous
1033  * characters in this sequence and return whether it is blocked or not.
1034  */
1035 static boolean_t
1036 blocked(uchar_t *comb_class, size_t last)
1037 {
1038 	uchar_t my_comb_class;
1039 	size_t i;
1040 
1041 	my_comb_class = comb_class[last];
1042 	for (i = 1; i < last; i++)
1043 		if (comb_class[i] >= my_comb_class ||
1044 		    comb_class[i] == U8_COMBINING_CLASS_STARTER)
1045 			return (B_TRUE);
1046 
1047 	return (B_FALSE);
1048 }
1049 
1050 /*
1051  * The do_composition() reads the character string pointed by 's' and
1052  * do necessary canonical composition and then copy over the result back to
1053  * the 's'.
1054  *
1055  * The input argument 's' cannot contain more than 32 characters.
1056  */
1057 static size_t
1058 do_composition(size_t uv, uchar_t *s, uchar_t *comb_class, uchar_t *start,
1059     uchar_t *disp, size_t last, uchar_t **os, uchar_t *oslast)
1060 {
1061 	uchar_t t[U8_STREAM_SAFE_TEXT_MAX + 1];
1062 	uchar_t tc[U8_MB_CUR_MAX] = { '\0' };
1063 	uint8_t saved_marks[U8_MAX_CHARS_A_SEQ];
1064 	size_t saved_marks_count;
1065 	uchar_t *p;
1066 	uchar_t *saved_p;
1067 	uchar_t *q;
1068 	size_t i;
1069 	size_t saved_i;
1070 	size_t j;
1071 	size_t k;
1072 	size_t l;
1073 	size_t C;
1074 	size_t saved_l;
1075 	size_t size;
1076 	uint32_t u1;
1077 	uint32_t u2;
1078 	boolean_t match_not_found = B_TRUE;
1079 
1080 	/*
1081 	 * This should never happen unless the callers are doing some strange
1082 	 * and unexpected things.
1083 	 *
1084 	 * The "last" is the index pointing to the last character not last + 1.
1085 	 */
1086 	if (last >= U8_MAX_CHARS_A_SEQ)
1087 		last = U8_UPPER_LIMIT_IN_A_SEQ;
1088 
1089 	for (i = l = 0; i <= last; i++) {
1090 		/*
1091 		 * The last or any non-Starters at the beginning, we don't
1092 		 * have any chance to do composition and so we just copy them
1093 		 * to the temporary buffer.
1094 		 */
1095 		if (i >= last || comb_class[i] != U8_COMBINING_CLASS_STARTER) {
1096 SAVE_THE_CHAR:
1097 			p = s + start[i];
1098 			size = disp[i];
1099 			for (k = 0; k < size; k++)
1100 				t[l++] = *p++;
1101 			continue;
1102 		}
1103 
1104 		/*
1105 		 * If this could be a start of Hangul Jamos, then, we try to
1106 		 * conjoin them.
1107 		 */
1108 		if (s[start[i]] == U8_HANGUL_JAMO_1ST_BYTE) {
1109 			U8_PUT_3BYTES_INTO_UTF32(u1, s[start[i]],
1110 			    s[start[i] + 1], s[start[i] + 2]);
1111 			U8_PUT_3BYTES_INTO_UTF32(u2, s[start[i] + 3],
1112 			    s[start[i] + 4], s[start[i] + 5]);
1113 
1114 			if (U8_HANGUL_JAMO_L(u1) && U8_HANGUL_JAMO_V(u2)) {
1115 				u1 -= U8_HANGUL_JAMO_L_FIRST;
1116 				u2 -= U8_HANGUL_JAMO_V_FIRST;
1117 				u1 = U8_HANGUL_SYL_FIRST +
1118 				    (u1 * U8_HANGUL_V_COUNT + u2) *
1119 				    U8_HANGUL_T_COUNT;
1120 
1121 				i += 2;
1122 				if (i <= last) {
1123 					U8_PUT_3BYTES_INTO_UTF32(u2,
1124 					    s[start[i]], s[start[i] + 1],
1125 					    s[start[i] + 2]);
1126 
1127 					if (U8_HANGUL_JAMO_T(u2)) {
1128 						u1 += u2 -
1129 						    U8_HANGUL_JAMO_T_FIRST;
1130 						i++;
1131 					}
1132 				}
1133 
1134 				U8_SAVE_HANGUL_AS_UTF8(t + l, 0, 1, 2, u1);
1135 				i--;
1136 				l += 3;
1137 				continue;
1138 			}
1139 		}
1140 
1141 		/*
1142 		 * Let's then find out if this Starter has composition
1143 		 * mapping.
1144 		 */
1145 		p = find_composition_start(uv, s + start[i], disp[i]);
1146 		if (p == NULL)
1147 			goto SAVE_THE_CHAR;
1148 
1149 		/*
1150 		 * We have a Starter with composition mapping and the next
1151 		 * character is a non-Starter. Let's try to find out if
1152 		 * we can do composition.
1153 		 */
1154 
1155 		saved_p = p;
1156 		saved_i = i;
1157 		saved_l = l;
1158 		saved_marks_count = 0;
1159 
1160 TRY_THE_NEXT_MARK:
1161 		q = s + start[++i];
1162 		size = disp[i];
1163 
1164 		/*
1165 		 * The next for() loop compares the non-Starter pointed by
1166 		 * 'q' with the possible (joinable) characters pointed by 'p'.
1167 		 *
1168 		 * The composition final table entry pointed by the 'p'
1169 		 * looks like the following:
1170 		 *
1171 		 * +---+---+---+-...-+---+---+---+---+-...-+---+---+
1172 		 * | C | b0| b2| ... | bn| F | B0| B1| ... | Bm| F |
1173 		 * +---+---+---+-...-+---+---+---+---+-...-+---+---+
1174 		 *
1175 		 * where C is the count byte indicating the number of
1176 		 * mapping pairs where each pair would be look like
1177 		 * (b0-bn F, B0-Bm F). The b0-bn are the bytes of the second
1178 		 * character of a canonical decomposition and the B0-Bm are
1179 		 * the bytes of a matching composite character. The F is
1180 		 * a filler byte after each character as the separator.
1181 		 */
1182 
1183 		match_not_found = B_TRUE;
1184 
1185 		for (C = *p++; C > 0; C--) {
1186 			for (k = 0; k < size; p++, k++)
1187 				if (*p != q[k])
1188 					break;
1189 
1190 			/* Have we found it? */
1191 			if (k >= size && *p == U8_TBL_ELEMENT_FILLER) {
1192 				match_not_found = B_FALSE;
1193 
1194 				l = saved_l;
1195 
1196 				while (*++p != U8_TBL_ELEMENT_FILLER)
1197 					t[l++] = *p;
1198 
1199 				break;
1200 			}
1201 
1202 			/* We didn't find; skip to the next pair. */
1203 			if (*p != U8_TBL_ELEMENT_FILLER)
1204 				while (*++p != U8_TBL_ELEMENT_FILLER)
1205 					;
1206 			while (*++p != U8_TBL_ELEMENT_FILLER)
1207 				;
1208 			p++;
1209 		}
1210 
1211 		/*
1212 		 * If there was no match, we will need to save the combining
1213 		 * mark for later appending. After that, if the next one
1214 		 * is a non-Starter and not blocked, then, we try once
1215 		 * again to do composition with the next non-Starter.
1216 		 *
1217 		 * If there was no match and this was a Starter, then,
1218 		 * this is a new start.
1219 		 *
1220 		 * If there was a match and a composition done and we have
1221 		 * more to check on, then, we retrieve a new composition final
1222 		 * table entry for the composite and then try to do the
1223 		 * composition again.
1224 		 */
1225 
1226 		if (match_not_found) {
1227 			if (comb_class[i] == U8_COMBINING_CLASS_STARTER) {
1228 				i--;
1229 				goto SAVE_THE_CHAR;
1230 			}
1231 
1232 			saved_marks[saved_marks_count++] = i;
1233 		}
1234 
1235 		if (saved_l == l) {
1236 			while (i < last) {
1237 				if (blocked(comb_class, i + 1))
1238 					saved_marks[saved_marks_count++] = ++i;
1239 				else
1240 					break;
1241 			}
1242 			if (i < last) {
1243 				p = saved_p;
1244 				goto TRY_THE_NEXT_MARK;
1245 			}
1246 		} else if (i < last) {
1247 			p = find_composition_start(uv, t + saved_l,
1248 			    l - saved_l);
1249 			if (p != NULL) {
1250 				saved_p = p;
1251 				goto TRY_THE_NEXT_MARK;
1252 			}
1253 		}
1254 
1255 		/*
1256 		 * There is no more composition possible.
1257 		 *
1258 		 * If there was no composition what so ever then we copy
1259 		 * over the original Starter and then append any non-Starters
1260 		 * remaining at the target string sequentially after that.
1261 		 */
1262 
1263 		if (saved_l == l) {
1264 			p = s + start[saved_i];
1265 			size = disp[saved_i];
1266 			for (j = 0; j < size; j++)
1267 				t[l++] = *p++;
1268 		}
1269 
1270 		for (k = 0; k < saved_marks_count; k++) {
1271 			p = s + start[saved_marks[k]];
1272 			size = disp[saved_marks[k]];
1273 			for (j = 0; j < size; j++)
1274 				t[l++] = *p++;
1275 		}
1276 	}
1277 
1278 	/*
1279 	 * If the last character is a Starter and if we have a character
1280 	 * (possibly another Starter) that can be turned into a composite,
1281 	 * we do so and we do so until there is no more of composition
1282 	 * possible.
1283 	 */
1284 	if (comb_class[last] == U8_COMBINING_CLASS_STARTER) {
1285 		p = *os;
1286 		saved_l = l - disp[last];
1287 
1288 		while (p < oslast) {
1289 			size = u8_number_of_bytes[*p];
1290 			if (size <= 1 || (p + size) > oslast)
1291 				break;
1292 
1293 			saved_p = p;
1294 
1295 			for (i = 0; i < size; i++)
1296 				tc[i] = *p++;
1297 
1298 			q = find_composition_start(uv, t + saved_l,
1299 			    l - saved_l);
1300 			if (q == NULL) {
1301 				p = saved_p;
1302 				break;
1303 			}
1304 
1305 			match_not_found = B_TRUE;
1306 
1307 			for (C = *q++; C > 0; C--) {
1308 				for (k = 0; k < size; q++, k++)
1309 					if (*q != tc[k])
1310 						break;
1311 
1312 				if (k >= size && *q == U8_TBL_ELEMENT_FILLER) {
1313 					match_not_found = B_FALSE;
1314 
1315 					l = saved_l;
1316 
1317 					while (*++q != U8_TBL_ELEMENT_FILLER) {
1318 						/*
1319 						 * This is practically
1320 						 * impossible but we don't
1321 						 * want to take any chances.
1322 						 */
1323 						if (l >=
1324 						    U8_STREAM_SAFE_TEXT_MAX) {
1325 							p = saved_p;
1326 							goto SAFE_RETURN;
1327 						}
1328 						t[l++] = *q;
1329 					}
1330 
1331 					break;
1332 				}
1333 
1334 				if (*q != U8_TBL_ELEMENT_FILLER)
1335 					while (*++q != U8_TBL_ELEMENT_FILLER)
1336 						;
1337 				while (*++q != U8_TBL_ELEMENT_FILLER)
1338 					;
1339 				q++;
1340 			}
1341 
1342 			if (match_not_found) {
1343 				p = saved_p;
1344 				break;
1345 			}
1346 		}
1347 SAFE_RETURN:
1348 		*os = p;
1349 	}
1350 
1351 	/*
1352 	 * Now we copy over the temporary string to the target string.
1353 	 * Since composition always reduces the number of characters or
1354 	 * the number of characters stay, we don't need to worry about
1355 	 * the buffer overflow here.
1356 	 */
1357 	for (i = 0; i < l; i++)
1358 		s[i] = t[i];
1359 	s[l] = '\0';
1360 
1361 	return (l);
1362 }
1363 
1364 /*
1365  * The collect_a_seq() function checks on the given string s, collect
1366  * a sequence of characters at u8s, and return the sequence. While it collects
1367  * a sequence, it also applies case conversion, canonical or compatibility
1368  * decomposition, canonical decomposition, or some or all of them and
1369  * in that order.
1370  *
1371  * The collected sequence cannot be bigger than 32 characters since if
1372  * it is having more than 31 characters, the sequence will be terminated
1373  * with a U+034F COMBINING GRAPHEME JOINER (CGJ) character and turned into
1374  * a Stream-Safe Text. The collected sequence is always terminated with
1375  * a null byte and the return value is the byte length of the sequence
1376  * including 0. The return value does not include the terminating
1377  * null byte.
1378  */
1379 static size_t
1380 collect_a_seq(size_t uv, uchar_t *u8s, uchar_t **source, uchar_t *slast,
1381     boolean_t is_it_toupper, boolean_t is_it_tolower,
1382     boolean_t canonical_decomposition, boolean_t compatibility_decomposition,
1383     boolean_t canonical_composition,
1384     int *errnum, u8_normalization_states_t *state)
1385 {
1386 	uchar_t *s;
1387 	int sz;
1388 	int saved_sz;
1389 	size_t i;
1390 	size_t j;
1391 	size_t k;
1392 	size_t l;
1393 	uchar_t comb_class[U8_MAX_CHARS_A_SEQ];
1394 	uchar_t disp[U8_MAX_CHARS_A_SEQ];
1395 	uchar_t start[U8_MAX_CHARS_A_SEQ];
1396 	uchar_t u8t[U8_MB_CUR_MAX] = { '\0' };
1397 	uchar_t uts[U8_STREAM_SAFE_TEXT_MAX + 1];
1398 	uchar_t tc;
1399 	size_t last;
1400 	size_t saved_last;
1401 	uint32_t u1;
1402 
1403 	/*
1404 	 * Save the source string pointer which we will return a changed
1405 	 * pointer if we do processing.
1406 	 */
1407 	s = *source;
1408 
1409 	/*
1410 	 * The following is a fallback for just in case callers are not
1411 	 * checking the string boundaries before the calling.
1412 	 */
1413 	if (s >= slast) {
1414 		u8s[0] = '\0';
1415 
1416 		return (0);
1417 	}
1418 
1419 	/*
1420 	 * As the first thing, let's collect a character and do case
1421 	 * conversion if necessary.
1422 	 */
1423 
1424 	sz = u8_number_of_bytes[*s];
1425 
1426 	if (sz < 0) {
1427 		*errnum = EILSEQ;
1428 
1429 		u8s[0] = *s++;
1430 		u8s[1] = '\0';
1431 
1432 		*source = s;
1433 
1434 		return (1);
1435 	}
1436 
1437 	if (sz == 1) {
1438 		if (is_it_toupper)
1439 			u8s[0] = U8_ASCII_TOUPPER(*s);
1440 		else if (is_it_tolower)
1441 			u8s[0] = U8_ASCII_TOLOWER(*s);
1442 		else
1443 			u8s[0] = *s;
1444 		s++;
1445 		u8s[1] = '\0';
1446 	} else if ((s + sz) > slast) {
1447 		*errnum = EINVAL;
1448 
1449 		for (i = 0; s < slast; )
1450 			u8s[i++] = *s++;
1451 		u8s[i] = '\0';
1452 
1453 		*source = s;
1454 
1455 		return (i);
1456 	} else {
1457 		if (is_it_toupper || is_it_tolower) {
1458 			i = do_case_conv(uv, u8s, s, sz, is_it_toupper);
1459 			s += sz;
1460 			sz = i;
1461 		} else {
1462 			for (i = 0; i < sz; )
1463 				u8s[i++] = *s++;
1464 			u8s[i] = '\0';
1465 		}
1466 	}
1467 
1468 	/*
1469 	 * And then canonical/compatibility decomposition followed by
1470 	 * an optional canonical composition. Please be noted that
1471 	 * canonical composition is done only when a decomposition is
1472 	 * done.
1473 	 */
1474 	if (canonical_decomposition || compatibility_decomposition) {
1475 		if (sz == 1) {
1476 			*state = U8_STATE_START;
1477 
1478 			saved_sz = 1;
1479 
1480 			comb_class[0] = 0;
1481 			start[0] = 0;
1482 			disp[0] = 1;
1483 
1484 			last = 1;
1485 		} else {
1486 			saved_sz = do_decomp(uv, u8s, u8s, sz,
1487 			    canonical_decomposition, state);
1488 
1489 			last = 0;
1490 
1491 			for (i = 0; i < saved_sz; ) {
1492 				sz = u8_number_of_bytes[u8s[i]];
1493 
1494 				comb_class[last] = combining_class(uv,
1495 				    u8s + i, sz);
1496 				start[last] = i;
1497 				disp[last] = sz;
1498 
1499 				last++;
1500 				i += sz;
1501 			}
1502 
1503 			/*
1504 			 * Decomposition yields various Hangul related
1505 			 * states but not on combining marks. We need to
1506 			 * find out at here by checking on the last
1507 			 * character.
1508 			 */
1509 			if (*state == U8_STATE_START) {
1510 				if (comb_class[last - 1])
1511 					*state = U8_STATE_COMBINING_MARK;
1512 			}
1513 		}
1514 
1515 		saved_last = last;
1516 
1517 		while (s < slast) {
1518 			sz = u8_number_of_bytes[*s];
1519 
1520 			/*
1521 			 * If this is an illegal character, an incomplete
1522 			 * character, or an 7-bit ASCII Starter character,
1523 			 * then we have collected a sequence; break and let
1524 			 * the next call deal with the two cases.
1525 			 *
1526 			 * Note that this is okay only if you are using this
1527 			 * function with a fixed length string, not on
1528 			 * a buffer with multiple calls of one chunk at a time.
1529 			 */
1530 			if (sz <= 1) {
1531 				break;
1532 			} else if ((s + sz) > slast) {
1533 				break;
1534 			} else {
1535 				/*
1536 				 * If the previous character was a Hangul Jamo
1537 				 * and this character is a Hangul Jamo that
1538 				 * can be conjoined, we collect the Jamo.
1539 				 */
1540 				if (*s == U8_HANGUL_JAMO_1ST_BYTE) {
1541 					U8_PUT_3BYTES_INTO_UTF32(u1,
1542 					    *s, *(s + 1), *(s + 2));
1543 
1544 					if (U8_HANGUL_COMPOSABLE_L_V(*state,
1545 					    u1)) {
1546 						i = 0;
1547 						*state = U8_STATE_HANGUL_LV;
1548 						goto COLLECT_A_HANGUL;
1549 					}
1550 
1551 					if (U8_HANGUL_COMPOSABLE_LV_T(*state,
1552 					    u1)) {
1553 						i = 0;
1554 						*state = U8_STATE_HANGUL_LVT;
1555 						goto COLLECT_A_HANGUL;
1556 					}
1557 				}
1558 
1559 				/*
1560 				 * Regardless of whatever it was, if this is
1561 				 * a Starter, we don't collect the character
1562 				 * since that's a new start and we will deal
1563 				 * with it at the next time.
1564 				 */
1565 				i = combining_class(uv, s, sz);
1566 				if (i == U8_COMBINING_CLASS_STARTER)
1567 					break;
1568 
1569 				/*
1570 				 * We know the current character is a combining
1571 				 * mark. If the previous character wasn't
1572 				 * a Starter (not Hangul) or a combining mark,
1573 				 * then, we don't collect this combining mark.
1574 				 */
1575 				if (*state != U8_STATE_START &&
1576 				    *state != U8_STATE_COMBINING_MARK)
1577 					break;
1578 
1579 				*state = U8_STATE_COMBINING_MARK;
1580 COLLECT_A_HANGUL:
1581 				/*
1582 				 * If we collected a Starter and combining
1583 				 * marks up to 30, i.e., total 31 characters,
1584 				 * then, we terminate this degenerately long
1585 				 * combining sequence with a U+034F COMBINING
1586 				 * GRAPHEME JOINER (CGJ) which is 0xCD 0x8F in
1587 				 * UTF-8 and turn this into a Stream-Safe
1588 				 * Text. This will be extremely rare but
1589 				 * possible.
1590 				 *
1591 				 * The following will also guarantee that
1592 				 * we are not writing more than 32 characters
1593 				 * plus a NULL at u8s[].
1594 				 */
1595 				if (last >= U8_UPPER_LIMIT_IN_A_SEQ) {
1596 TURN_STREAM_SAFE:
1597 					*state = U8_STATE_START;
1598 					comb_class[last] = 0;
1599 					start[last] = saved_sz;
1600 					disp[last] = 2;
1601 					last++;
1602 
1603 					u8s[saved_sz++] = 0xCD;
1604 					u8s[saved_sz++] = 0x8F;
1605 
1606 					break;
1607 				}
1608 
1609 				/*
1610 				 * Some combining marks also do decompose into
1611 				 * another combining mark or marks.
1612 				 */
1613 				if (*state == U8_STATE_COMBINING_MARK) {
1614 					k = last;
1615 					l = sz;
1616 					i = do_decomp(uv, uts, s, sz,
1617 					    canonical_decomposition, state);
1618 					for (j = 0; j < i; ) {
1619 						sz = u8_number_of_bytes[uts[j]];
1620 
1621 						comb_class[last] =
1622 						    combining_class(uv,
1623 						    uts + j, sz);
1624 						start[last] = saved_sz + j;
1625 						disp[last] = sz;
1626 
1627 						last++;
1628 						if (last >=
1629 						    U8_UPPER_LIMIT_IN_A_SEQ) {
1630 							last = k;
1631 							goto TURN_STREAM_SAFE;
1632 						}
1633 						j += sz;
1634 					}
1635 
1636 					*state = U8_STATE_COMBINING_MARK;
1637 					sz = i;
1638 					s += l;
1639 
1640 					for (i = 0; i < sz; i++)
1641 						u8s[saved_sz++] = uts[i];
1642 				} else {
1643 					comb_class[last] = i;
1644 					start[last] = saved_sz;
1645 					disp[last] = sz;
1646 					last++;
1647 
1648 					for (i = 0; i < sz; i++)
1649 						u8s[saved_sz++] = *s++;
1650 				}
1651 
1652 				/*
1653 				 * If this is U+0345 COMBINING GREEK
1654 				 * YPOGEGRAMMENI (0xCD 0x85 in UTF-8), a.k.a.,
1655 				 * iota subscript, and need to be converted to
1656 				 * uppercase letter, convert it to U+0399 GREEK
1657 				 * CAPITAL LETTER IOTA (0xCE 0x99 in UTF-8),
1658 				 * i.e., convert to capital adscript form as
1659 				 * specified in the Unicode standard.
1660 				 *
1661 				 * This is the only special case of (ambiguous)
1662 				 * case conversion at combining marks and
1663 				 * probably the standard will never have
1664 				 * anything similar like this in future.
1665 				 */
1666 				if (is_it_toupper && sz >= 2 &&
1667 				    u8s[saved_sz - 2] == 0xCD &&
1668 				    u8s[saved_sz - 1] == 0x85) {
1669 					u8s[saved_sz - 2] = 0xCE;
1670 					u8s[saved_sz - 1] = 0x99;
1671 				}
1672 			}
1673 		}
1674 
1675 		/*
1676 		 * Let's try to ensure a canonical ordering for the collected
1677 		 * combining marks. We do this only if we have collected
1678 		 * at least one more non-Starter. (The decomposition mapping
1679 		 * data tables have fully (and recursively) expanded and
1680 		 * canonically ordered decompositions.)
1681 		 *
1682 		 * The U8_SWAP_COMB_MARKS() convenience macro has some
1683 		 * assumptions and we are meeting the assumptions.
1684 		 */
1685 		last--;
1686 		if (last >= saved_last) {
1687 			for (i = 0; i < last; i++)
1688 				for (j = last; j > i; j--)
1689 					if (comb_class[j] &&
1690 					    comb_class[j - 1] > comb_class[j]) {
1691 						U8_SWAP_COMB_MARKS(j - 1, j);
1692 					}
1693 		}
1694 
1695 		*source = s;
1696 
1697 		if (! canonical_composition) {
1698 			u8s[saved_sz] = '\0';
1699 			return (saved_sz);
1700 		}
1701 
1702 		/*
1703 		 * Now do the canonical composition. Note that we do this
1704 		 * only after a canonical or compatibility decomposition to
1705 		 * finish up NFC or NFKC.
1706 		 */
1707 		sz = do_composition(uv, u8s, comb_class, start, disp, last,
1708 		    &s, slast);
1709 	}
1710 
1711 	*source = s;
1712 
1713 	return ((size_t)sz);
1714 }
1715 
1716 /*
1717  * The do_norm_compare() function does string comparison based on Unicode
1718  * simple case mappings and Unicode Normalization definitions.
1719  *
1720  * It does so by collecting a sequence of character at a time and comparing
1721  * the collected sequences from the strings.
1722  *
1723  * The meanings on the return values are the same as the usual strcmp().
1724  */
1725 static int
1726 do_norm_compare(size_t uv, uchar_t *s1, uchar_t *s2, size_t n1, size_t n2,
1727     int flag, int *errnum)
1728 {
1729 	int result;
1730 	size_t sz1;
1731 	size_t sz2;
1732 	uchar_t u8s1[U8_STREAM_SAFE_TEXT_MAX + 1];
1733 	uchar_t u8s2[U8_STREAM_SAFE_TEXT_MAX + 1];
1734 	uchar_t *s1last;
1735 	uchar_t *s2last;
1736 	boolean_t is_it_toupper;
1737 	boolean_t is_it_tolower;
1738 	boolean_t canonical_decomposition;
1739 	boolean_t compatibility_decomposition;
1740 	boolean_t canonical_composition;
1741 	u8_normalization_states_t state;
1742 
1743 	s1last = s1 + n1;
1744 	s2last = s2 + n2;
1745 
1746 	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
1747 	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
1748 	canonical_decomposition = flag & U8_CANON_DECOMP;
1749 	compatibility_decomposition = flag & U8_COMPAT_DECOMP;
1750 	canonical_composition = flag & U8_CANON_COMP;
1751 
1752 	while (s1 < s1last && s2 < s2last) {
1753 		/*
1754 		 * If the current character is a 7-bit ASCII and the last
1755 		 * character, or, if the current character and the next
1756 		 * character are both some 7-bit ASCII characters then
1757 		 * we treat the current character as a sequence.
1758 		 *
1759 		 * In any other cases, we need to call collect_a_seq().
1760 		 */
1761 
1762 		if (U8_ISASCII(*s1) && ((s1 + 1) >= s1last ||
1763 		    ((s1 + 1) < s1last && U8_ISASCII(*(s1 + 1))))) {
1764 			if (is_it_toupper)
1765 				u8s1[0] = U8_ASCII_TOUPPER(*s1);
1766 			else if (is_it_tolower)
1767 				u8s1[0] = U8_ASCII_TOLOWER(*s1);
1768 			else
1769 				u8s1[0] = *s1;
1770 			u8s1[1] = '\0';
1771 			sz1 = 1;
1772 			s1++;
1773 		} else {
1774 			state = U8_STATE_START;
1775 			sz1 = collect_a_seq(uv, u8s1, &s1, s1last,
1776 			    is_it_toupper, is_it_tolower,
1777 			    canonical_decomposition,
1778 			    compatibility_decomposition,
1779 			    canonical_composition, errnum, &state);
1780 		}
1781 
1782 		if (U8_ISASCII(*s2) && ((s2 + 1) >= s2last ||
1783 		    ((s2 + 1) < s2last && U8_ISASCII(*(s2 + 1))))) {
1784 			if (is_it_toupper)
1785 				u8s2[0] = U8_ASCII_TOUPPER(*s2);
1786 			else if (is_it_tolower)
1787 				u8s2[0] = U8_ASCII_TOLOWER(*s2);
1788 			else
1789 				u8s2[0] = *s2;
1790 			u8s2[1] = '\0';
1791 			sz2 = 1;
1792 			s2++;
1793 		} else {
1794 			state = U8_STATE_START;
1795 			sz2 = collect_a_seq(uv, u8s2, &s2, s2last,
1796 			    is_it_toupper, is_it_tolower,
1797 			    canonical_decomposition,
1798 			    compatibility_decomposition,
1799 			    canonical_composition, errnum, &state);
1800 		}
1801 
1802 		/*
1803 		 * Now compare the two characters. If they are the same,
1804 		 * we move on to the next character sequences.
1805 		 */
1806 		if (sz1 == 1 && sz2 == 1) {
1807 			if (*u8s1 > *u8s2)
1808 				return (1);
1809 			if (*u8s1 < *u8s2)
1810 				return (-1);
1811 		} else {
1812 			result = strcmp((const char *)u8s1, (const char *)u8s2);
1813 			if (result != 0)
1814 				return (result);
1815 		}
1816 	}
1817 
1818 	/*
1819 	 * We compared until the end of either or both strings.
1820 	 *
1821 	 * If we reached to or went over the ends for the both, that means
1822 	 * they are the same.
1823 	 *
1824 	 * If we reached only one end, that means the other string has
1825 	 * something which then can be used to determine the return value.
1826 	 */
1827 	if (s1 >= s1last) {
1828 		if (s2 >= s2last)
1829 			return (0);
1830 		return (-1);
1831 	}
1832 	return (1);
1833 }
1834 
1835 /*
1836  * The u8_strcmp() function compares two UTF-8 strings quite similar to
1837  * the strcmp(). For the comparison, however, Unicode Normalization specific
1838  * equivalency and Unicode simple case conversion mappings based equivalency
1839  * can be requested and checked against.
1840  */
1841 int
1842 u8_strcmp(const char *s1, const char *s2, size_t n, int flag, size_t uv,
1843     int *errnum)
1844 {
1845 	int f;
1846 	size_t n1;
1847 	size_t n2;
1848 
1849 	*errnum = 0;
1850 
1851 	/*
1852 	 * Check on the requested Unicode version, case conversion, and
1853 	 * normalization flag values.
1854 	 */
1855 
1856 	if (uv > U8_UNICODE_LATEST) {
1857 		*errnum = ERANGE;
1858 		uv = U8_UNICODE_LATEST;
1859 	}
1860 
1861 	if (flag == 0) {
1862 		flag = U8_STRCMP_CS;
1863 	} else {
1864 		f = flag & (U8_STRCMP_CS | U8_STRCMP_CI_UPPER |
1865 		    U8_STRCMP_CI_LOWER);
1866 		if (f == 0) {
1867 			flag |= U8_STRCMP_CS;
1868 		} else if (f != U8_STRCMP_CS && f != U8_STRCMP_CI_UPPER &&
1869 		    f != U8_STRCMP_CI_LOWER) {
1870 			*errnum = EBADF;
1871 			flag = U8_STRCMP_CS;
1872 		}
1873 
1874 		f = flag & (U8_CANON_DECOMP | U8_COMPAT_DECOMP | U8_CANON_COMP);
1875 		if (f && f != U8_STRCMP_NFD && f != U8_STRCMP_NFC &&
1876 		    f != U8_STRCMP_NFKD && f != U8_STRCMP_NFKC) {
1877 			*errnum = EBADF;
1878 			flag = U8_STRCMP_CS;
1879 		}
1880 	}
1881 
1882 	if (flag == U8_STRCMP_CS) {
1883 		return (n == 0 ? strcmp(s1, s2) : strncmp(s1, s2, n));
1884 	}
1885 
1886 	n1 = strlen(s1);
1887 	n2 = strlen(s2);
1888 	if (n != 0) {
1889 		if (n < n1)
1890 			n1 = n;
1891 		if (n < n2)
1892 			n2 = n;
1893 	}
1894 
1895 	/*
1896 	 * Simple case conversion can be done much faster and so we do
1897 	 * them separately here.
1898 	 */
1899 	if (flag == U8_STRCMP_CI_UPPER) {
1900 		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
1901 		    n1, n2, B_TRUE, errnum));
1902 	} else if (flag == U8_STRCMP_CI_LOWER) {
1903 		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
1904 		    n1, n2, B_FALSE, errnum));
1905 	}
1906 
1907 	return (do_norm_compare(uv, (uchar_t *)s1, (uchar_t *)s2, n1, n2,
1908 	    flag, errnum));
1909 }
1910 
1911 size_t
1912 u8_textprep_str(char *inarray, size_t *inlen, char *outarray, size_t *outlen,
1913     int flag, size_t unicode_version, int *errnum)
1914 {
1915 	int f;
1916 	int sz;
1917 	uchar_t *ib;
1918 	uchar_t *ibtail;
1919 	uchar_t *ob;
1920 	uchar_t *obtail;
1921 	boolean_t do_not_ignore_null;
1922 	boolean_t do_not_ignore_invalid;
1923 	boolean_t is_it_toupper;
1924 	boolean_t is_it_tolower;
1925 	boolean_t canonical_decomposition;
1926 	boolean_t compatibility_decomposition;
1927 	boolean_t canonical_composition;
1928 	size_t ret_val;
1929 	size_t i;
1930 	size_t j;
1931 	uchar_t u8s[U8_STREAM_SAFE_TEXT_MAX + 1];
1932 	u8_normalization_states_t state;
1933 
1934 	if (unicode_version > U8_UNICODE_LATEST) {
1935 		*errnum = ERANGE;
1936 		return ((size_t)-1);
1937 	}
1938 
1939 	f = flag & (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER);
1940 	if (f == (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER)) {
1941 		*errnum = EBADF;
1942 		return ((size_t)-1);
1943 	}
1944 
1945 	f = flag & (U8_CANON_DECOMP | U8_COMPAT_DECOMP | U8_CANON_COMP);
1946 	if (f && f != U8_TEXTPREP_NFD && f != U8_TEXTPREP_NFC &&
1947 	    f != U8_TEXTPREP_NFKD && f != U8_TEXTPREP_NFKC) {
1948 		*errnum = EBADF;
1949 		return ((size_t)-1);
1950 	}
1951 
1952 	if (inarray == NULL || *inlen == 0)
1953 		return (0);
1954 
1955 	if (outarray == NULL) {
1956 		*errnum = E2BIG;
1957 		return ((size_t)-1);
1958 	}
1959 
1960 	ib = (uchar_t *)inarray;
1961 	ob = (uchar_t *)outarray;
1962 	ibtail = ib + *inlen;
1963 	obtail = ob + *outlen;
1964 
1965 	do_not_ignore_null = !(flag & U8_TEXTPREP_IGNORE_NULL);
1966 	do_not_ignore_invalid = !(flag & U8_TEXTPREP_IGNORE_INVALID);
1967 	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
1968 	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
1969 
1970 	ret_val = 0;
1971 
1972 	/*
1973 	 * If we don't have a normalization flag set, we do the simple case
1974 	 * conversion based text preparation separately below. Text
1975 	 * preparation involving Normalization will be done in the false task
1976 	 * block, again, separately since it will take much more time and
1977 	 * resource than doing simple case conversions.
1978 	 */
1979 	if (f == 0) {
1980 		while (ib < ibtail) {
1981 			if (*ib == '\0' && do_not_ignore_null)
1982 				break;
1983 
1984 			sz = u8_number_of_bytes[*ib];
1985 
1986 			if (sz < 0) {
1987 				if (do_not_ignore_invalid) {
1988 					*errnum = EILSEQ;
1989 					ret_val = (size_t)-1;
1990 					break;
1991 				}
1992 
1993 				sz = 1;
1994 				ret_val++;
1995 			}
1996 
1997 			if (sz == 1) {
1998 				if (ob >= obtail) {
1999 					*errnum = E2BIG;
2000 					ret_val = (size_t)-1;
2001 					break;
2002 				}
2003 
2004 				if (is_it_toupper)
2005 					*ob = U8_ASCII_TOUPPER(*ib);
2006 				else if (is_it_tolower)
2007 					*ob = U8_ASCII_TOLOWER(*ib);
2008 				else
2009 					*ob = *ib;
2010 				ib++;
2011 				ob++;
2012 			} else if ((ib + sz) > ibtail) {
2013 				if (do_not_ignore_invalid) {
2014 					*errnum = EINVAL;
2015 					ret_val = (size_t)-1;
2016 					break;
2017 				}
2018 
2019 				if ((obtail - ob) < (ibtail - ib)) {
2020 					*errnum = E2BIG;
2021 					ret_val = (size_t)-1;
2022 					break;
2023 				}
2024 
2025 				/*
2026 				 * We treat the remaining incomplete character
2027 				 * bytes as a character.
2028 				 */
2029 				ret_val++;
2030 
2031 				while (ib < ibtail)
2032 					*ob++ = *ib++;
2033 			} else {
2034 				if (is_it_toupper || is_it_tolower) {
2035 					i = do_case_conv(unicode_version, u8s,
2036 					    ib, sz, is_it_toupper);
2037 
2038 					if ((obtail - ob) < i) {
2039 						*errnum = E2BIG;
2040 						ret_val = (size_t)-1;
2041 						break;
2042 					}
2043 
2044 					ib += sz;
2045 
2046 					for (sz = 0; sz < i; sz++)
2047 						*ob++ = u8s[sz];
2048 				} else {
2049 					if ((obtail - ob) < sz) {
2050 						*errnum = E2BIG;
2051 						ret_val = (size_t)-1;
2052 						break;
2053 					}
2054 
2055 					for (i = 0; i < sz; i++)
2056 						*ob++ = *ib++;
2057 				}
2058 			}
2059 		}
2060 	} else {
2061 		canonical_decomposition = flag & U8_CANON_DECOMP;
2062 		compatibility_decomposition = flag & U8_COMPAT_DECOMP;
2063 		canonical_composition = flag & U8_CANON_COMP;
2064 
2065 		while (ib < ibtail) {
2066 			if (*ib == '\0' && do_not_ignore_null)
2067 				break;
2068 
2069 			/*
2070 			 * If the current character is a 7-bit ASCII
2071 			 * character and it is the last character, or,
2072 			 * if the current character is a 7-bit ASCII
2073 			 * character and the next character is also a 7-bit
2074 			 * ASCII character, then, we copy over this
2075 			 * character without going through collect_a_seq().
2076 			 *
2077 			 * In any other cases, we need to look further with
2078 			 * the collect_a_seq() function.
2079 			 */
2080 			if (U8_ISASCII(*ib) && ((ib + 1) >= ibtail ||
2081 			    ((ib + 1) < ibtail && U8_ISASCII(*(ib + 1))))) {
2082 				if (ob >= obtail) {
2083 					*errnum = E2BIG;
2084 					ret_val = (size_t)-1;
2085 					break;
2086 				}
2087 
2088 				if (is_it_toupper)
2089 					*ob = U8_ASCII_TOUPPER(*ib);
2090 				else if (is_it_tolower)
2091 					*ob = U8_ASCII_TOLOWER(*ib);
2092 				else
2093 					*ob = *ib;
2094 				ib++;
2095 				ob++;
2096 			} else {
2097 				*errnum = 0;
2098 				state = U8_STATE_START;
2099 
2100 				j = collect_a_seq(unicode_version, u8s,
2101 				    &ib, ibtail,
2102 				    is_it_toupper,
2103 				    is_it_tolower,
2104 				    canonical_decomposition,
2105 				    compatibility_decomposition,
2106 				    canonical_composition,
2107 				    errnum, &state);
2108 
2109 				if (*errnum && do_not_ignore_invalid) {
2110 					ret_val = (size_t)-1;
2111 					break;
2112 				}
2113 
2114 				if ((obtail - ob) < j) {
2115 					*errnum = E2BIG;
2116 					ret_val = (size_t)-1;
2117 					break;
2118 				}
2119 
2120 				for (i = 0; i < j; i++)
2121 					*ob++ = u8s[i];
2122 			}
2123 		}
2124 	}
2125 
2126 	*inlen = ibtail - ib;
2127 	*outlen = obtail - ob;
2128 
2129 	return (ret_val);
2130 }
2131 
2132 EXPORT_SYMBOL(u8_validate);
2133 EXPORT_SYMBOL(u8_strcmp);
2134 EXPORT_SYMBOL(u8_textprep_str);
2135